There are presently available many teaching aids such as those disclosed by Canadian Pat. Nos. 696,380, which issued to Graflex, Inc. on Oct. 20, 1964; 972,952, which issued to A. R. Schmoyer on Aug. 19, 1975 and 983,261, which issued to Kee, Incorporated on Feb. 10, 1976. Several U.S. patents also disclose educational games or devices, including U.S. Pat. Nos. 3,617,260, which issued to E. H. Shuford, Jr., et al on Oct. 19, 1971; 3,696,528, which issued to H. A. Mertz on Oct. 10, 1972, and 3,918,173, which issued to J. Logos on Nov. 11, 1975. Most such teaching aids are either relatively simple in structure and limited in scope and/or appeal, or complicated in structure and thus expensive to produce in large quantities.
Of the above patents, only Canadian Pat. No. 696,380 discloses an apparatus of the type proposed by applicant. One embodiment of the patented apparatus includes a casing with an opening containing a mask. The mask includes a transparent portion and an opaque portion. Paper bearing questions and answers is fed to the mask, the question being visible through the transparent portion and the answers being hidden by the opaque portion. A student writes his answer to the question on the paper using an opening provided for such purpose, and then advances the paper to view the correct answer previously hidden by the mask. A second embodiment of the apparatus includes separate question sheets and an expendable strip of paper for answers. Such an apparatus is useful for older students who can write, but cannot be used by younger students who have not learned to write.
There exists a need for a teaching apparatus which is simple in structure and operation, and capable of capturing the attention of the students, particularly younger students.